Because most of us need the eggs.

"I thought of this old joke, you know, this guy goes to a psychiatrist and says: "Doc, my brother is crazy. He thinks he's a chicken." The Doctor says "well, why don't you turn him in?" And the guy says, "I would, but I need the eggs." Well I guess this is how I pretty much feel about relationships. You know they're totally irrational and absurd and... but, I guess we keep going through it because most of us need the eggs."
- Annie Hall